boot_fit: Create helper functions that can be used to select DTB out of FIT

Some platforms may append a FIT image to the U-boot image. This function
aids in parsing the FIT image and selecting the correct DTB at runtime.

Signed-off-by: Franklin S Cooper Jr <fcooper@ti.com>
Reviewed-by: Tom Rini <trini@konsulko.com>

common/Kconfig

@@ -437,6 +437,13 @@ config SYS_STDIO_DEREGISTER
 
 endmenu
 
+config FIT_EMBED
+	bool "Support a FIT image embedded in the U-boot image"
+	help
+	  This option provides hooks to allow U-boot to parse an
+	  appended FIT image and enable board specific code to then select
+	  the correct DTB to be used.
+
 config DEFAULT_FDT_FILE
 	string "Default fdt file"
 	help

common/Makefile

@@ -151,6 +151,7 @@ obj-y += image.o
 obj-$(CONFIG_ANDROID_BOOT_IMAGE) += image-android.o
 obj-$(CONFIG_$(SPL_)OF_LIBFDT) += image-fdt.o
 obj-$(CONFIG_$(SPL_)FIT) += image-fit.o
+obj-$(CONFIG_FIT_EMBED) += boot_fit.o common_fit.o
 obj-$(CONFIG_$(SPL_)FIT_SIGNATURE) += image-sig.o
 obj-$(CONFIG_IO_TRACE) += iotrace.o
 obj-y += memsize.o

common/boot_fit.c

@@ -0,0 +1,80 @@
+/*
+ * (C) Copyright 2017
+ * Texas Instruments, <www.ti.com>
+ *
+ * Franklin S Cooper Jr. <fcooper@ti.com>
+ *
+ * SPDX-License-Identifier:     GPL-2.0+
+ */
+
+#include <boot_fit.h>
+#include <common.h>
+#include <errno.h>
+#include <image.h>
+#include <libfdt.h>
+
+int fdt_offset(void *fit)
+{
+	int images, node, fdt_len, fdt_node, fdt_offset;
+	const char *fdt_name;
+
+	node = fit_find_config_node(fit);
+	if (node < 0)
+		return node;
+
+	images = fdt_path_offset(fit, FIT_IMAGES_PATH);
+	if (images < 0) {
+		debug("%s: Cannot find /images node: %d\n", __func__, images);
+		return FDT_ERROR;
+	}
+
+	fdt_name = fdt_getprop(fit, node, FIT_FDT_PROP, &fdt_len);
+	if (!fdt_name) {
+		debug("%s: Cannot find fdt name property: %d\n",
+		      __func__, fdt_len);
+		return -EINVAL;
+	}
+
+	fdt_node = fdt_subnode_offset(fit, images, fdt_name);
+	if (fdt_node < 0) {
+		debug("%s: Cannot find fdt node '%s': %d\n",
+		      __func__, fdt_name, fdt_node);
+		return -EINVAL;
+	}
+
+	fdt_offset = fdt_getprop_u32(fit, fdt_node, "data-offset");
+
+	if (fdt_offset == FDT_ERROR)
+		return -ENOENT;
+
+	fdt_len = fdt_getprop_u32(fit, fdt_node, "data-size");
+
+	if (fdt_len < 0)
+		return fdt_len;
+
+	return fdt_offset;
+}
+
+void *locate_dtb_in_fit(void *fit)
+{
+	struct image_header *header;
+	int size;
+	int ret;
+
+	size = fdt_totalsize(fit);
+	size = (size + 3) & ~3;
+
+	header = (struct image_header *)fit;
+
+	if (image_get_magic(header) != FDT_MAGIC) {
+		debug("No FIT image appended to U-boot\n");
+		return NULL;
+	}
+
+	ret = fdt_offset(fit);
+
+	if (ret <= 0)
+		return NULL;
+	else
+		return (void *)fit+size+ret;
+}

include/boot_fit.h

@@ -0,0 +1,9 @@
+/*
+ * Copyright (C) 2017 Texas Instruments
+ * Written by Franklin Cooper Jr. <fcooper@ti.com>
+ *
+ * SPDX-License-Identifier:     GPL-2.0+
+ */
+
+int fdt_offset(void *fit);
+void *locate_dtb_in_fit(void *fit);

include/image.h

@@ -1272,6 +1272,9 @@ void board_fit_image_post_process(void **p_image, size_t *p_size);
 
 #define FDT_ERROR	((ulong)(-1))
 
+ulong fdt_getprop_u32(const void *fdt, int node, const char *prop);
+int fit_find_config_node(const void *fdt);
+
 /**
  * Mapping of image types to function handlers to be invoked on the associated
  * loaded images